info:eu-repo/semantics/article
First detection of a transferable bla CTX-M-14b gene in a Klebsiella pneumoniae clinical isolate from Tunisia and analysis of its genetic context
Fecha
2012-03Registro en:
Ben Achour, Nahed; Power, Pablo; Mercuri, Pablo Alberto; Moussa, Mohamed Ben; Moreno, Galleni; et al.; First detection of a transferable bla CTX-M-14b gene in a Klebsiella pneumoniae clinical isolate from Tunisia and analysis of its genetic context; Inst Microbiologia; Annals Of Microbiology; 62; 4; 3-2012; 1737-1742
1590-4261
CONICET Digital
CONICET
Autor
Ben Achour, Nahed
Power, Pablo
Mercuri, Pablo Alberto
Moussa, Mohamed Ben
Moreno, Galleni
Omrane. Belhadj
Resumen
Klebsiella pneumoniae ML2508 was isolated from a patient at the surgery unit of the Military Hospital (Hôpital Militaire de Tunis), Tunisia. It was identified as a producer of extended-spectrum β-lactamases (ESBLs) by the double-disk synergy test. The β-lactamases produced by the strain were characterized by isoelectric focusing, determination of the specific activities against penicillins and cephalosporins, determination of the inhibitory concentration required to inhibit 50% of enzyme activity (IC50), and the inhibition effect of EDTA on putative metallo-β- lactamases. The crude extract of K. pneumoniae ML2508 contains five different β-lactamases with pI 5.5, 7.3, 7.6, 8.1, and 8.6. Only the β-lactamase with pI 8.1 was transferred by transformation and conjugation experiments. Molecular characterization of these genes was performed by PCR and sequencing. The four chromosomal β-lactamases are TEM (pI 5.5), 2 SHV (pI 7.3 and 7.6), and CTX-M-28 (pI 8.6). The β-lactamase with pI 8.1 was encoded by blaCTX-M-14b gene located on a 50-kb highly conjugative plasmid. The study of the genetic context of blaCTX-M-14b was realized by PCR-mapping and DNA sequencing. A novel variant of tnpISEcp1 designated ISEcp1C was detected upstream of the gene.